Lapidary / Gemstone Community Forum

I keep seeing information that indicates that rocks should not be allowed to freeze. I know that rocks in this area of Maine freeze every year. I plan on storing my rocks out side and am now wondering how they will be affected if allowed them to freeze. I see all the piles in the back yard shops out west but I am not sure if they freeze in those areas. My mind keeps reminding me that they are just rocks , millions of years old with plenty of exposure.

I am from Washington state and previously from Oregon and The only thing that I can think of might have to do with the rocks fracturing from having  the moisture in them freeze.  Otherwise, in my short span of 69 years of wisdom, I don't see much of any other reason to worry whether the freeze or not.

-=Will=-

Pourous rocks can get water soaked and fracture if frozen.  Most stone will be unaffected but I would not leave $150 a pound dino bone out in the yard to freeze.

YOu know I dont know nuttin about nuttin but I love to do research:)
http://www.waterencyclopedia.com/Tw-Z/Weathering-of-Rocks.html

If your rocks have cracks in them the freeze thaw cycle will make the cracks bigger or make larger pieces into smaller pieces. Most solid rocks have no problems weathering out a winter. It is the water getting into the cracks and freezing that does the damage, so if you are worried about it you could tarp them or put a roof over them to keep the water off of them. I have lots of rocks outside all winter, some turn into tumbling rough, some do just fine.
I find  my rocks cut better during the winter than they do during the summer, so I do the majority of my cutting during the winter, Also less maintenance problems with the saws during the winter.
I also  have more free time during the winter to cut with so it works well for me.

Tony

With freezing  and thawing water being the primary enemy of rocks, my suggestion is to just throw a waterproof tarp over them in the winter.

thanks all. I liked the website on weathering. great info. I have them on pallets off of the ground in wooden boxes that are covered from rain . The ones that I buy are inside in sheds. The more expensive ones are in the basement that never freezes. I should be good.  Thanks again all. I will sleep better now.

Nice link !

My main concern would be to make sure the rocks have time to acclimate to room temperature before cutting or grinding them.  In the winter here, it can be -20 outside and we keep it in the 60s inside.  I find that my preforms from upstairs chip and crack less when i use luke warm water rather than cold water from the faucet.  Cutting and grinding heat up the stone and if the water is cold, there can be quite a temp difference between them.  Maybe this isn't that big a deal in some warmer climates, but I have a lot less problems with cracking and chipping now.

Alvin, I am thinking that the freeze thaw cracks happen mostly while they are still in the ground. All rocks will absorb a certain amount of moisture, (if they didn't absorb water, we would never be able to get a specific gravity) and while in the ground and dirt, they are probably closer to their saturation point. 
Then, lets say the frost line goes down 30 inches, those ice crystals gotta go somewhere. I imagine that as a rock gets closer to the surface it goes through more and more freezing and thawing cycles, therefore they are most likely to be to their ultimate damage point, before they get into our oily, grubby rock cutting and grinding hands. It's a wonder how all those surface collected rocks, are as solid as they are, but we still have fun with them!

Please explain ???

Please explain ???

     i personally sleep better knowing that all my rocks are comfortable and clean  hide35

Alvin, I am a certified aggregate technician. To do a specific gravity for rocks, I have to submerse them in water for a minimum of 17 hours, then I dry the exterior of the rock and weigh it, then weigh it submerged in water. Then we put the rock in an 220 degree oven overnight, cool then weigh it again. Various calculations give you specific gravity, absorption rate and etc. that we use.
Specific gravity, is the weight of some thing in water as compared to what it weighs normally. This is why a piece of gold the size of a walnut, weighs more than the walnut.
Or density, is another way to look at it!

LOLOLOL Jon:)
Thanks Hulagrub for the explanation. Its good to learn something new:)

It sounds like when the rock gets on the surface, the worst damage has been done. The  rocks in the tidal water that I pick, not only get to be in and out of water while freezing every six hours, but get beat up in the water also. So the way I see it, once I save them from the beach, they should keep better under my care even if they are allowed to freeze when dry. That sure sounds like a real tec. job.  If you can get them to pay you for cutting the rocks too, you would have a rock hound dream job.

I still do not understand why we would not be able to get a specific gravity - your exmple of gold, for instance, does not absorb water, yet it has a specific gravity (density that is). 

What you are doing, I think, is measuring two different specific gravities. The first one with absorbed water, and the second one without.

As I write this I think maybe this is a way of eliminating the effect of any voids in the rock by filling it with water and then eliminating it.

but still   "could not measure a sp grav"?

Maybe a part of the absorption test. Wouldn't water add to the dry weight but be weightless in water? Geez thats beecause Iuse the specific gravities of gold and quartz. I do not have to find the water displacement! I have never had to soak gold specimens before doing SG tests. Speaking of which........In 1983 I found a pocket of highgrade gold that had frost wedged out of the wall rock right at the portal of an old adit. Recovered almost 38 ozs of gold! The Old Timers missed it.  yippie24

After all the freezing, thawing, meteorites, volanic activity for millions of years I think the rocks have proven themselves to be very durable no matter what the weather is. 

Bob WOW 38 oz. What a find!!! You could have bought a house with that, back then.
     Gregor and Bob, well think about the absorption, if the water has not filled in the voids of a rock, then when you check for specific gravity, air would cause the rock to be lighter as compared to the water.
     Think about two 1 oz. pieces of agate. One is very solid, one is full of visible pits, (the key word here, visible). Now if the one is of lesser specific gravity, would it still be a type of quartz? Is it still as hard, yes? Or?

Very interesting, but I would like to point out the finding specific gravity is not reliant on a substances ability to absorb water as you initially stated.